Download The laterl wall of the nose consists of medial surface of maxilla

NASOPHARYNGEAL ANGIOFIBROMA
ANATOMICAL CONSIDERATIONS
The lateral wall of the nose consists of medial surface of maxilla, overlapped from above by
the parts of ethmoid bone, from behind by the perpendicular plate of the palatine bone and
below by the inferior concha.
The sphenopalatine foramen is situated just behind the posterior end of the middle turbinate,
which is part of the ethmoid.
This foramen is formed by two processes of the perpendicular plate of the palatine bone and
body of the sphenoid bone. This foramen serves as a communication between nasal cavity
and pterygo-palatine fossa. Through this foramen pass the sphenopalatine vessels and nasal
and nasoplatine nerves emanating from sphenoplatine ganglion situated in the
pterygopalatine fossa.
The pterygopalatine fossa is situated deep below the apex of the orbit. This is bounded
anteriorly by posterior surface of the maxilla and posteriorly mostly by anterior surface of
greater wing of sphenoid. Laterally the fossa opens into infratemporal fossa through the
pterygomaxillary fissure. Another important relation of PP Fossa is with the orbit anteriorly
through the inferior orbital fissure.
The PP Fossa is located at strategic crossroad and has a number of communications. As
stated earlier anteriorly it communicates with orbit via inferior orbital fissure. Once
pathology reaches orbit it can further spread to base of skull via superior orbital fissure.
Laterally it communicates with infratemporal fossa, which lies skull in the region of middle
cranial fossa through pterygomaxillary fissure. The infratemporal fossa further leads to
temporal fossa through a gap beneath zygomatic arch. This allows the spread of pathology
towards the check.
Another important communication is with the middle cranial fossa through the foramen
rotundum and with foramen lacerum through pterygoid canal.
Angiofibroma: The term angiofibroma denotes a vascular swelling presenting in the
nasopharynx of the pre pubertal and adolescent males and exhibiting a tendency to bleed.
Pathology: Grossly the angiofibromata appear as firm slightly spongy lobulated swelling,
the nodularity of which increases with age. The tumour lacks a true capsule.
The colour of tumour varies from pink to white.The part which can be seen the nasopharnx
and is hence covered with mucous membrane is pink in colour and the part which escapes to
adjacent extra-pharyngeal areas are white in colour.
Microscopically the picture is of vascular spaces with varying shapes and sizes, abounding in
a stroma of fibrous tissue. The proportion of fibrous tissue alters with age of swelling. In the
younger lesion the vascular component stands out as all pervasive feature, whereas in older
swellings collagen element predominates.
Pathogenesis: A number of theories have been proposed:
 Tumour arises from periosteum of the nasopharyngeal vault.
 There are inequalities in growth of bones forming the skull base result in hypertrophy
of the underlying periosteum in response to hormonal influences.
 Tumour arises from embryonic fibrocartilage between basiocciput and basisphenoid.
 Possibly the swellings are hamartomas or residues of fetal erectile tissue which were
subjected to hormonal influences.
 Possiblity of vascular malformations- angiofibromata arise from vestiges of atrophied
stapedial artery.
Site of origin and behaviour of angiofibromata: It was previously assumed that vault of
nasppharynx was most likely site of origin, because of the broad base of attachment of the
tumour to the skull base.
Others considered the choana to be a more possible site of origin in view of the frequency
with which both nasopharynx and nasal fossa are involved.
Modern methods of investigation and surgery have focused attention on the region of
sphenopalatine foramen as site of origin which would explain the subsequent behaviour of
angiofibromata.
This is based on the observation that larger tumour present as bilobed dumb-bell shaped
swellings straddling the sphenoplatine formen, with one component filling the nasopharynx
and other extending out pterygopalatine and infratemporal fossa.
The seedling swelling arising from such a site would migrate under the mucous membrane,
eventually growing to fill post-nasal space. As the process of growth continues anterior face
of sphenoid sinus is eroded and the sinus is invaded. Following the path of least resistence
and grows into nasal fossa where it may acquire secondary attchments. Having filled the
nasal fossa, it displaces the nasal septum to opposite side causing bilateral nasal blockade.
Lateral spread already described.
That portion of the bilobed angiofibroma which lies outside nasopharynx eventually
becomes very hard and nodular.
The main blood supply of the angiofibromata comes by way of an enlarged maxillary artery.
Symptoms and signs: The two cardinal symptoms of angiofibroma are nasal obstruction
and intermittent epistaxis. The epistaxis may vary in severity from occasional shows to an
alarming and some times life threatening torrent. Chronic anaemia is thus acommon feature
of established condition.
The voice acquires a nasal annotation. Blockage of Eustachian tube is not uncommon in such
a situation and leads to deafness and otalgia.
Abundant purulent secretions, together with bowing of nasal septum to other side.
Obvious swelling of the check and temple. Impaction of the bulky disease in IFTF results in
extreme signs such as trismus and bulging of parotid gland. Proptosis is a definite sign that
orbital fissures have been penetrated.
Headache, failing vision.
Investigations:
 X-ray PNS opacity of sinuses
 Lateral tomograms reveal forward bowing of posterior antral wall
 CT/ MRI
 Selective arteriography.
 Biopsy is no longer justified.
DD:
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AC Polyp
Large adenoids
Tumours of Post-nasal space
Chordoma
Treatment:
The two primary therapeutic modalities for JNA over the years have been surgery and
radiotherapy. Several adjunctive measures have been tried, including embolization, hormonal
therapy, and chemotherapy. The main concerns with radiotherapy, which is delivered by
external beam, are malignancies in the irradiated field and the danger of inhibiting normal
facial growth in younger patients. Cummings found that, although symptomatic relief is fast,
regression of tumor with radiation is slow. In his study, 50% of patients treated with primary
radiotherapy had visible tumor in the nasopharynx or nasal cavity 12 months after treatment.
Fifty percent of patients who had visible tumor at two years suffered eventual recurrence.
Most recurrences after radiotherapy have been blamed on geographic misses, but some
authors have blamed inadequate dosing. The proper dosage of radiotherapy is debated.
Cummings et al declared 30 Gy for three weeks adequate for tumor control, and found no
greater control at higher dosages. Economou et al from UCLA found doses of more that 36
Gy to be required for adequate tumor control. Some have suggested 30 to 35 Gy for
moderately-sized tumors, with larger doses for extensive tumors. McGahan et al from Baylor
recommend primary irradiation for intracranial tumor using 40 to 46 Gy with 180 cGy
fractions.
Most authors prefer surgical treatment in all patients with extracranial disease, and reserve
radiation for "unresectable" intracranial tumors or as post-operative adjunctive therapy when
residual tumor has to be left behind. Concerns with surgical management include intra-
operative death secondary to exsanguination, tumor recurrence, and intra-operative injury to
vital structures during attempted resection. In the literature, tumor control rates with a single
surgical procedure generally range from 70% to 90%.
Many surgical approaches have been used against JNA. The decision regarding approach is
usually made after reviewing radiographic studies to assess tumor extent, blood supply, and
presence or absence of intracranial extension. Midfacial degloving provides good exposure
to the target area with excellent cosmesis. Techniques have been combined as necessary to
provide full exposure for most tumors. In the case of JNA with extreme lateral extension, a
transzygomatic infratemporal approach has been used. Intracranial JNA is estimated to occur
in 20% to 25% of cases. Operative complication, recurrence, and mortality are all closely
linked to intracranial extension. Invasion lateral to the cavernous sinus is generally
considered resectable, while invasion of the sinus itself or medial penetration, with
involvement of chiasm and/or pituitary, is generally deemed unresectable and treated with
radiotherapy.
Our experience at Baylor suggests that most extracranial tumors can be controlled in one
procedure with a carefully planned approach, but that recurrences can occur at all tumor
stages. Likewise, most intracranial tumors can be controlled with 40 to 46 Gy of
radiotherapy with low morbidity.